Paul McCartney began January 9, 1969, at the piano sketching out “Another Day,” but it was anything but for the sixth day of the Beatles’ sessions at Twickenham, where things started to get a little testy, while musically it remained deeply compelling.

Just another day: The Beatles begin their second week at Twickenham with Paul at the piano and his muse by his side as he debuts an important future solo classic.

Road work: Twickenham is Paul’s songwriting lab as the morning’s tapes reveal his effort to put lyrics to several works-in-progress, like “Carry That Weight” and “The Long and Winding Road,” among others.

Last-night song: George Harrison lifts the veil on a proper version of “For You Blue,” but are the other Beatles eager to bite on another George original?

Jokes in between: Harmony and discord, joy and petulance. It’s a roller-coaster of moods for the members of the Beatles as they continued work on their core set at Twickenham.

Another kind of gig: Get yourself well done with the backstory of the Beatles’ lively and perpetually mysterious “Suzy Parker.”

Love from Paul: Take an exceedingly deep dive into Paul McCartney’s “Penina,” one of the most obscure originals from the Beatles era and a “£20,000 holiday tip.”

No Pakistanis: Inspired by current events, Paul McCartney works on a set of satirical, racially charged — and later misunderstood — lyrics to “Get Back.” Putting this Beatles’ session into appropriate context 50 years later.

Power politics: “This racial business over in England” inspires a suite of upbeat, satirical improvisations. This is the story of The Beatles​’ “Commonwealth” and “Get Off.”

Subconscious sabotage: To his death, John Lennon hated the recording of “Across the Universe.” But with a chance to make it anew during The Beatles’ Get Back sessions, instead of changing his world, the song would slip away.

It’s dead easy: An inspired Paul McCartney & Co. raid the toolbox to effortlessly shape “Let It Be” into a more coherent, familiar song. Here’s the origin story of the riffs, harmonies and arrangement with far more detail than you likely asked for.

Homeward bounder: After flirting the night before with the idea of a sea cruise to Libya, The Beatles’ enthusiasm for show-boating waned as Ringo Starr preached mundanity over spectacle for a planned live performance.

Crossroads he’s standing at: How a pair of covers of yet-to-be-released Bob Dylan songs sheds light on George Harrison’s disposition the afternoon before he’d walk out on The Beatles.

Et cetera: Putting a bow on The Beatles’ busy January 9, 1969. Featuring “Junk” and “Teddy Boy” from Paul, some proto-punk from John, bugs that aren’t Beatles and more.